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Texas Instruments INA125UA/2K5
- Part No.:
- INA125UA/2K5
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
INA125UA/2K5.pdf
- Description:
- IC INST AMP 1 CIRCUIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,357
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Product details
Overview
INA125UA/2K5 from Texas Instruments (originally Burr-Brown) is a precision instrumentation amplifier with integrated voltage reference, designed for bridge sensor signal conditioning in industrial and battery-powered systems. It delivers 250 µV max input offset voltage, 100 dB min CMR at G=100, and selectable 2.5 V / 5 V / 10 V reference outputs - enabling direct excitation of strain gauge and RTD bridges.
For engineers reviewing the INA125UA/2K5 datasheet, INA125UA/2K5 pinout, INA125UA/2K5 application, or INA125UA/2K5 equivalent, key selection criteria include its single-resistor gain setting (G = 4 + 60 kΩ/RG), ±40 V input protection, sleep-mode quiescent current ≤25 µA, and SOIC-16 package compatibility with automated SMT assembly.
Technical Context
The INA125UA/2K5 integrates two precision op amps (A1 and A2) in a three-op-amp instrumentation topology with laser-trimmed internal resistors, enabling high common-mode rejection and low drift. Its reference section uses ratio-trimmed bandgap circuitry to deliver 2.5 V, 5 V, or 10 V outputs with ±0.5% initial accuracy and ±35 ppm/°C max drift.
Gain is set externally via resistor RG between pins 8 and 9, with internal 60 kΩ metal-film resistors contributing directly to gain accuracy and temperature coefficient. The SLEEP pin enables logic-controlled shutdown, reducing supply current to ±1 µA while maintaining high-impedance output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Offset Voltage | 250 µV max (RTI, initial) - ensures sub-0.01% error in 10 mV full-scale bridge outputs |
| CMR @ G=100 | 100 dB min - rejects >99.99% of common-mode noise in noisy factory environments |
| Reference Accuracy | ±0.5% max (2.5/5/10 V) - eliminates need for external reference trimming in ratiometric ADC systems |
| Quiescent Current | 460 µA typical - supports >1-year operation on 200 mAh coin cell in portable data loggers |
| Sleep Current | ±25 µA max - enables duty-cycled acquisition with <1 µA average system power |
| Input Protection | ±40 V absolute max - withstands ESD and transients without external clamping diodes |
| Supply Range | +2.7 V to +36 V single supply - operates directly from 3.3 V microcontrollers or 24 V industrial rails |
Pinout & Package
INA125UA/2K5 is housed in a 16-pin SOIC (SO-16) surface-mount package with standard 1.27 mm pitch, JEDEC MS-012AC compliant, and rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (V+) | Positive Supply Input | Accepts +2.7 V to +36 V; powers all internal amplifiers and reference |
| 2 (SLEEP) | Shutdown Control Input | Logic-low (≤100 mV) disables amplifiers and reference, reducing IQ to µA range |
| 3 (V–) | Negative Supply Input | Connect to ground (single supply) or negative rail (dual supply); sets output swing limits |
| 4 (VREFOUT) | Reference Output Terminal | Delivers selected 2.5/5/10 V reference; must connect to VREF2.5/VREF5/VREF10 to activate |
| 5 (IAREF) | Instrumentation Amp Reference | Output common-mode reference point; must be low-impedance grounded for >90 dB CMR |
| 6 (VIN–) | Inverting Input | Differential input node; requires bias current return path (e.g., matched resistors to IAREF) |
| 7 (VIN+) | Non-inverting Input | Differential input node; protected to ±40 V; same bias path requirement as VIN– |
| 8,9 (RG) | External Gain Resistor Terminals | RG sets gain per G = 4 + 60 kΩ/RG; values from 6 Ω (G=10k) to open (G=4) |
| 10 (VO) | Amplifier Output | Single-ended output referenced to IAREF; swings to within 1.2 V of rails at G=4 |
| 11 (Sense) | Reference Current Sense | Monitors reference load current; used for external current boosting (e.g., with TIP29C transistor) |
| 12 (VREF10) | 10 V Reference Select | Connect VREFOUT to this pin to configure 10 V reference output |
| 13 (VREFBG) | Bandgap Reference (1.24 V) | Provides 1.24 V ±0.5% output; usable when V+ ≥ 2.7 V |
| 14 (VREF2.5) | 2.5 V Reference Select | Connect VREFOUT to enable 2.5 V reference; optimal for 3.3 V systems with ratiometric ADCs |
| 15 (VREF5) | 5 V Reference Select | Enables 5 V reference; matches legacy 5 V ADCs and microcontroller analog inputs |
| 16 (VREFCOM) | Reference Common | Reference ground return; carries ~180 µA; must connect to low-impedance system ground |
Key Features
| Feature | Design Value |
|---|---|
| Single-resistor programmable gain | Gain from 4 to 10,000 set by one external RG, eliminating complex resistor networks and trimming |
| Precision integrated voltage reference | Four selectable reference outputs (1.24 V, 2.5 V, 5 V, 10 V) with ±0.5% accuracy - removes external reference IC and reduces BOM count |
| Low-power sleep mode | Reduces total supply current to ±25 µA max, enabling ultra-low-power wake-up sampling in IoT sensor nodes |
| Robust ±40 V input protection | Withstands overvoltage without external components - simplifies front-end design for field-installed sensors |
| Laser-trimmed DC performance | 250 µV max offset and 2 µV/°C max drift ensure stable measurements across industrial temperature ranges |
| Wide single-supply operation | Operates from +2.7 V to +36 V - supports both battery-powered handheld tools and 24 V PLC I/O modules |
Applications
| Pressure Transducer Signal Conditioning | Multi-Channel Industrial Data Acquisition |
|---|---|
Use Scenario: Amplifying mV-level differential output from stainless-steel strain gauge pressure sensors in HVAC control panels. IC Role / Device Role / Timing Role: Provides complete bridge excitation (via VREFOUT → VREF10) and precision differential amplification (G=100–500) in one IC. Use Value: Eliminates separate reference and amplifier ICs, reducing layout area by 40% and improving thermal tracking between reference and gain stages. | Use Scenario: Simultaneous monitoring of 8 thermocouple channels in a programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: Acts as channelized front-end amplifier with individual gain and reference selection per channel. Use Value: Enables ratiometric measurement using 2.5 V reference with 16-bit SAR ADCs, achieving <0.02% total unadjusted error across –20°C to +70°C. |
| Battery-Powered Portable Weigh Scale | Factory Automation Load Cell Interface |
Use Scenario: Signal conditioning for aluminum-alloy load cells in handheld retail scales powered by two AA batteries. IC Role / Device Role / Timing Role: Delivers low-noise amplification (38 nV/√Hz) and sleep-mode power management for 30-day battery life. Use Value: Sleep current ≤25 µA allows 100-ms wake-up bursts every 2 seconds, extending battery life beyond 1,000 hours. | Use Scenario: High-reliability interface between 4-wire load cells and EtherCAT I/O terminals in automotive assembly lines. IC Role / Device Role / Timing Role: Provides ESD-hardened (±40 V) input stage and 100 dB CMR to reject 50/60 Hz line noise in electrically noisy shop floors. Use Value: Maintains 16-bit effective resolution despite 10 Vpp common-mode interference from nearby servo drives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar instrumentation amplifier with reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD8226ARMZ | Single-supply only (+3.3 V to +36 V); no integrated reference; 200 µV max offset; 35 nV/√Hz noise | Requires external reference IC (e.g., REF192) for bridge excitation; better noise performance but higher BOM cost | Select when lowest noise is critical and reference can be sourced separately; not suitable for space-constrained designs needing integrated reference |
| INA333AIDR | Zerø-drift architecture; 25 µV max offset; 1.6 µV/°C max drift; no integrated reference; SO-8 package | Superior DC stability for long-term drift-sensitive applications (e.g., medical weight scales); lacks bridge excitation capability | Select for ultra-low drift requirements where external reference is acceptable; incompatible with single-chip bridge solutions |
Compared with AD8226ARMZ and INA333AIDR, the INA125UA/2K5 uniquely combines laser-trimmed precision, integrated multi-voltage reference, and ±40 V input protection in SO-16 - making it the only drop-in solution for compact, self-contained bridge amplifier designs requiring minimal external components.
Availability
INA125UA/2K5 is available at Aetrix Electronics and suitable for pressure transducer interfaces, multi-channel data acquisition systems, and battery-powered portable instrumentation requiring stable component supply and long-lifecycle support.
Supply support for INA125UA/2K5 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments acquired Burr-Brown in 2000 and maintains full production and technical support for legacy precision analog products including the INA125 series.
The INA125 product line was engineered specifically for high-accuracy sensor signal conditioning in industrial process control and factory automation - integrating reference and amplification to minimize calibration complexity and PCB area.
FAQ
What is the maximum gain achievable with INA125UA/2K5, and how is it set?
The INA125UA/2K5 supports gains from 4 to 10,000, set by a single external resistor RG connected between pins 8 and 9 per the equation G = 4 + 60 kΩ/RG. For G = 10,000, RG = 6 Ω (6.04 Ω 1% standard value). At highest gains, wiring resistance and socket contact resistance become significant sources of error, so direct soldering of RG is recommended for production designs using INA125UA/2K5.
Can INA125UA/2K5 operate from a 3.3 V supply, and what reference voltage options are available?
Yes, INA125UA/2K5 operates from +2.7 V to +36 V single supply. At 3.3 V, only the 2.5 V reference (VREFOUT → VREF2.5) and 1.24 V bandgap (VREFOUT → VREFBG) are valid, since V+ must exceed the selected reference by ≥1.25 V. The 2.5 V option is ideal for ratiometric measurement with 3.3 V ADCs, delivering ±0.5% accuracy and ±35 ppm/°C drift - fully specified for use with INA125UA/2K5 under these conditions.
How does the SLEEP pin function, and what is the wake-up time for INA125UA/2K5?
The SLEEP pin (pin 2) places INA125UA/2K5 into shutdown when pulled ≤100 mV relative to VREFCOM, reducing quiescent current to ±25 µA max. Wake-up occurs when SLEEP rises ≥2.7 V, with full DC performance restored in <150 µs (typical). During wake-up, input offset voltage settles to final value within 50 µs, ensuring accurate first-sample acquisition - critical for time-triggered sampling in INA125UA/2K5-based data loggers.
What is the purpose of the Sense pin (pin 11) on INA125UA/2K5, and when should it be used?
The Sense pin (pin 11) monitors reference output current and enables external current boosting using an NPN transistor (e.g., TIP29C) as shown in Figure 4 of the INA125UA/2K5 datasheet. It is required when driving reference loads >5 mA (e.g., multiple bridge sensors or high-current ADC references), preventing reference voltage droop and maintaining ±0.5% accuracy. For ≤2 mA loads, Sense may be left unconnected - a key design flexibility built into INA125UA/2K5.
Does INA125UA/2K5 require external input protection when used with industrial sensors?
No - INA125UA/2K5 features built-in ±40 V input protection on both VIN+ and VIN– pins, allowing direct connection to strain gauges, RTDs, and other industrial sensors without external TVS diodes or series resistors. This protection remains active even with supplies disconnected, safeguarding the device during handling and field maintenance. The internal protection limits input current to 120–190 µA during overload, preserving long-term reliability of INA125UA/2K5 in harsh environments.
INA125UA/2K5 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Instrumentation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 0.2V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 150 kHz
- Current - Input Bias:
- 10 nA
- Voltage - Input Offset:
- 50 µV
- Current - Supply:
- 460µA
- Current - Output / Channel:
- 12 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
INA125UA/2K5 FAQ
1.How can I place an order for INA125UA/2K5 through Aetrix?
Please submit a Request for Quotation (RFQ) for INA125UA/2K5 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for INA125UA/2K5 reliable?
The price and inventory of INA125UA/2K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA125UA/2K5 is usually 5 days.
3.What payment methods are accepted for INA125UA/2K5?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA125UA/2K5 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for INA125UA/2K5?
INA125UA/2K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your INA125UA/2K5 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for INA125UA/2K5?
For technical support, including INA125UA/2K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA125UA/2K5 requirements.
6.How does Aetrix verify that INA125UA/2K5 is sourced from the original manufacturer or authorized distributors?
All INA125UA/2K5 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that INA125UA/2K5 meets industry standards.
7.What is the process for return or replacement of INA125UA/2K5?
All INA125UA/2K5 units undergo pre-shipment inspection (PSI). If there is an issue with INA125UA/2K5, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The INA125UA/2K5 part is unused and in its original packaging.
Return procedure for INA125UA/2K5:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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